Hyperspectral Characteristics of Canopy Components and Structure for Phenological Assessment of an Invasive Weed

Spectral reflectance values of four canopy components (stems, buds, opening flowers, and postflowers of yellow starthistle (Centaurea solstitialis)) were measured to describe their spectral characteristics. We then physically combined these canopy components to simulate the flowering stage indicated by accumulated flower ratios (AFR) 10%, 40%, 70%, and 90%, respectively. Spectral dissimilarity and spectral angles were calculated to quantitatively identify spectral differences among canopy components and characteristic patterns of these flowering stages. This study demonstrated the ability of hyperspectral data to characterize canopy components, and identify different flowering stages. Stems had a typical spectral profile of green vegetation, which produced a spectral dissimilarity with three reproduction organs (buds, opening flowers, and postflowers). Quantitative differences between simulated flower stages depended on spectral regions and phenological stages examined. Using full-range canopy spectra, the initial flowering stage could be separated from the early peak, peak, and late flowering stages by three spectral regions, i.e. the blue absorption (around 480 nm) and red absorption (around 650 nm) regions and NIR plateau from 730 nm to 950 nm. For airborne CASI data, only the red absorption region and NIR plateau could be used to identify the flowering stages in the field. This study also revealed that the peak flowering stage was more easily recognized than any of the other three stages.     

Effects of predation risk and hunger on the behaviour of two species of tadpoles

Predation and hunger are threats for most organisms, and appropriate behavioural responses to both factors should be shaped by natural selection. In combination, however, the behavioural demands of predation avoidance and effective foraging often cannot be satisfied at the same time and lead to a conflict within organisms. We examined the behavioural responses of two closely-related species of tadpoles, Rana lessonae and R. esculenta, to simulated predation by fish and hunger. Tadpoles, hatched and reared in the laboratory, were tested in a three-way factorial (predation risk × hunger × species) experiment with four predation levels and four hunger levels. Both species decreased their swimming activity with increasing predation risk. Predation risk did not influence the amount of activity time invested in feeding but caused the tadpoles to spend less time in patches with food. Refuges were not used to avoid predation. R. esculenta was more sensitive to predation risk than R. lessonae. Hunger increased both the activity of tadpoles and the amount of activity time invested in feeding, thus indicating an increased energy intake. No interactions were observed between predation risk and hunger. These results show that tadpoles possess genetically-based behavioural mechanisms that allow them to respond in a graded manner to predation and hunger. However, they did not balance the two conflicting demands of predation avoidance and effective foraging; the two mechanisms appeared to act independently. Correspondence to: R.D. Semlitsch     

Assessing conservation opportunity on private land: socio-economic, behavioral, and spatial dimensions

This study presents a method for assessing conservation opportunity on private land based on landholders' socio-economic, behavioral, and farm characteristics. These characteristics include age, gender, education, level of off-farm income, farm size, proportion of remnant native vegetation on-farm, and ecological value of native vegetation on-farm. A sample of landholders who own greater than 2 ha of land in the South Australian Murray-Darling Basin region were sent a mail-based survey about their values and preferences for environmental management (N = 659, 52% response). Cross-tabulations and ANOVA statistical analysis techniques were used to compare the socio-economic attributes across three landholder classes: disengaged, moderately engaged, and highly engaged in native vegetation planting. Results indicate that highly engaged landholders were more likely to be female, formally educated, hobby farmers who managed small parcels of land and have high off-farm incomes, whereas disengaged landholders held significantly stronger farming connections (more farming experience, family have lived on the farm for more generations). Spatial analysis revealed area-specific differences in conservation opportunity and conservation priority. In some areas, properties of high ecological value were managed by highly engaged landholders, but nearby properties of high value were managed by moderately engaged or disengaged landholders. Environmental managers therefore cannot assume areas of high conservation priority will be areas of high conservation opportunity. At the regional scale, the potential for revegetation seems most promising within the moderately engaged landholder group considering the vast amount of land managed by this group in areas of high ecological value, particularly within the less represented Mallee and Coorong and Rangelands sub-regions. We suggest that incentive schemes which purchase conservation need to be targeted at disengaged landholders; mentoring schemes led by commercial farmers highly engaged in native vegetation planting should be directed at moderately engaged landholders, and; awards programs which acknowledge conservation successes should be targeted at highly engaged landholders.     

Drought frequency in the Volta Basin of West Africa

According to various reports, climate change is responsible for the change in rainfall amount and pattern accompanied by the various degrees of extreme events in Sahelian West Africa in recent years. Other reports also suggest that there has been a “recovery” of the rainy season (Nicholson 2005). In this study, temporal characteristics of meteorological droughts in the Volta basin, a semi-arid region in West Africa, are investigated in order to provide a guide for sustainable water resource management. For this purpose, drought intensity, areal extent and recurrence frequency is analysed using the standardised precipitation index (SPI) for a time series between 1961 and 2005 from 52 meteorology stations across the Volta basin. Using this analysis the severity of the historical droughts of 1961, 1970, 1983, 1992 and 2001 that occurred in the region are assessed and their intensity, areal extent and return periods are obtained. The drought intensity is lower than −2.0 over nearly 75% of the region, meaning that a major part of the region was under extreme drought conditions during this year. The drought of 1983/1984 has a probability of occurrence of up to 0.1 from records spanning 44 years. The areal extent of extreme drought conditions is about 90% during this drought period.     

Comparison of Wind at 500 Feet Over Minneapolis and Louisville With Geostrophic Wind

Measurements of wind speed at 500 ft on a television tower in the Minneapolis-St. Paul area are compared with geostrophic wind speeds and lapse rates. The roughness length for the builtr-up area surrounding the tower is estimated using geostrophic boundary-layer models. Similar data for Louisville are also considered. The results are relevant to-the application of existing boundary-layer models to the estimation of wind speed and turbulent mixing over a city.     

Recommendations on the Use of Satellite Remote-Sensing Data for Urban Air Quality

Abstract

In the last 5 yr, the capabilities of earth-observing satellites and the technological tools to share and use satellite data have advanced sufficiently to consider using satellite imagery in conjunction with ground-based data for urban-scale air quality monitoring. Satellite data can add synoptic and geospatial information to ground-based air quality data and modeling. An assessment of the integrated use of ground-based and satellite data for air quality monitoring, including several short case studies, was conducted. Findings identified current U.S. satellites with potential for air quality applications, with others available internationally and several more to be launched within the next 5 yr; several of these sensors are described in this paper as illustrations. However, use of these data for air quality applications has been hindered by historical lack of collaboration between air quality and satellite scientists, difficulty accessing and understanding new data, limited resources and agency priorities to develop new techniques, ill-defined needs, and poor understanding of the potential and limitations of the data. Specialization in organizations and funding sources has limited the resources for cross-disciplinary projects. To successfully use these new data sets requires increased collaboration between organizations, streamlined access to data, and resources for project implementation.     

Applicability of hydromorphological monitoring data to locate flood risk reduction measures: Blanice River basin, Czech Republic

This paper presents a new methodological approach, using hydromorphological monitoring data from river networks, to identify stream elements that may negatively influence the course of floods, as well as elements suitable for modifications that will reinforce the natural retention potential of the floodplain. The approach uses data derived from hydromorphological monitoring that conforms to the EN 14614 standard "Water quality--Guidance standard for assessing the hydromorphological features of rivers." Four major aspects of stream modifications that can potentially affect the course and consequences of floods, and that can be derived from hydromorphological monitoring, were identified. These are: (1) modifications that increase the speed of runoff, (2) modifications that restrict the retention potential of the floodplain, (3) potential obstacles to the flood course, and (4) improper alterations of stream route modifications. A GIS is used to identify and locate these critical aspects of stream and floodplain modification. This method was applied in the Blanice River basin, an area in central Europe hit by a severe flood in August 2002. The critical modifications identified were compared with geomorphological mapping to display the different effects of individual types of modifications.     

INTEGRATING SERVICE‐LEARNING INTO WATERSHED MANAGEMENT PROGRAMS: OPPORTUNITIES AND CHALLENGES1

ABSTRACT: The objective of this article is to open a dialogue on integrating service‐learning into community based watershed management programs and to discuss opportunities and challenges that a service‐learning program presents to universities and communities. The article presents the concept and definition of service‐learning, and arguments concerning why institutions of higher education and university faculty and students should be involved with community based watershed management programs. The article describes a case study for developing a service‐learning program for watershed management at Virginia Tech and discusses lessons learned from the case study. The paper concluded that to make a service‐learning program sustainable, there should be a long term plan, regular and effective communication with the stakeholders, and some incentives for faculty and students for long term commitment to the community based watershed management programs.     

Building a Sustainable Future for Animal Agriculture: An Environmental Virtue Ethic of Care Approach within the Philosophy of Technology

Agricultural technologies are non-neutral and ethical challenges are posed by these technologies themselves. The technologies we use or endorse are embedded with values and norms and reflect the shape of our moral character. They can literally make us better or worse consumers and/or people. Looking back, when the world’s developed nations welcomed and steadily embraced industrialization as the dominant paradigm for agriculture a half century or so ago, they inadvertently championed a philosophy of technology that promotes an insular human-centricism, despite its laudable intent to ensure food security and advance human flourishing. The dominant philosophy of technology has also seeded particular ethical consequences that plague the well-being of human beings, the planet, and farmed animals. After revisiting some fundamental questions regarding the complex ways in which technology as agent shapes our lives and choices and relegates food and farmed constituents into technological artifacts or commodities, I argue that we should accord an environmental virtue ethic of care—understood as caretaking—a central place in developing a more conscientious philosophy of technology that aims at sustainability, fairness, and humaneness in animal agriculture. While technology shapes society, it also is socially shaped and an environmental virtue ethic of care (EVEC) as an alternative design philosophy has the tools to help us take a much overdue inventory of ourselves and our relationships with the nonhuman world. It can help us to expose the ways in which technology hinders critical reflection of its capacity to alter communities and values, to come to terms with why we may be, in general, disengaged from critical ethical analysis of contemporary agriculture and to consider the moral shape and trajectory and the sustainability of our food production systems going into the future. I end by outlining particular virtues associated with the ethic of care discussed here and consider some likely implications for consumers and industry technocrats as they relate to farming animals.     

Recovery of Sediment Characteristics in Moraine,Headwater Streams of Northern Minnesota After Forest Harvest1

Merten, Eric C., Nathaniel A. Hemstad, Randall K. Kolka, Raymond M. Newman, Elon S. Verry, and Bruce Vondracek, 2010. Recovery of Sediment Characteristics in Moraine, Headwater Streams of Northern Minnesota After Forest Harvest. Journal of the American Water Resources Association (JAWRA) 46(4): 733-743. DOI: 10.1111/j.1752-1688.2010.00445.x Abstract: We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.